// APS101, Winter 2009: Lecture 28 (Mar. 19)
//
// Review: last time we began writing a Tic-Tac-Toe game.

// This will be good practice for A3!

// The first component of a game is the "engine":
// the behind-the-scenes work that is done by the
// program, which allows the user to play the game.
// (however, it's not very user-friendly - which is 
//  why we need to write a GUI for the game later!)

// We already wrote the constructor and the setMark methods.

// Now, we need to visualize the game, as follows:

// empty grid:
 | |
- - -
 | |
- - -
 | |

// or:
X| |
- - -
O|O|
- - -
 | |

// Notice the repetition in this visual representation.
// i.e., we can use loops to make this drawing!

// (see the toString() method in TicTacToe.java)

// What other functionality does a game have?
// well, usually at some point one player wins the game.

// How many ways are there to win in Tic-Tac-Toe?
// 1) horizontally
// 2) vertically
// 3) diagonally

// (see methods rowWinner, colWinner, and diagWinner in TicTacToe.java)

// Pay special attention to the LOGIC behind your code!
// we had problems writing diagWinner because of some very small
// errors in the for-loops.

// These are called run-time errors (as opposed to syntax errors), and
// they are much harder to debug!